JPH08225159A - Paper feeder - Google Patents

Abstract

PURPOSE: To reduce a fluctuation in pushing up force of a bottom plate according to a mounting quantity of paper by positioning a center of rotation on a bisector substantially perpendicular to a line connecting both engaging points with a tongue in both boundary positions in a movable area for a paper mounting member and eliminating an unnecessary contact fluctuation between the bottom plate and the tip of the tongue. CONSTITUTION: In a bottom plate 2 in a waiting condition, a pressing point by a tongue 6 is assumed to be a point C1 . A point, at which the point C1 arrives when the bottom plate 2 is moved upward to the uppermost position, is assumed to be a point C2 . A rotation fulcrum O2 of the tongue 6 is positioned on the vertical bisector of a solid line connecting the both points C1 , C2 . Then, the tip of the tongue 6 pushes up the bottom plate 2 while being brought into contact with the substantially same point on the lower face of the rotating bottom plate 2. As the bottom plate 2 is lifted up by means of the tongue 6 touching the substantially same position regardless of a mounting quantity of paper, a fluctuation, which is due to a mounting quantity of paper, in lifting force of the bottom plate 2 is lowered.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a sheet feeding device in a copying machine, a printer or the like, and more particularly to a sheet feeding device in which a bottom plate of a sheet tray is lifted up by rotation of a tongue (pushing member). It is a thing.

[0002]

2. Description of the Related Art In this type of sheet feeding device, as means for raising the uppermost sheet to a sheet feeding position regardless of the amount of sheets stacked in a sheet tray, Japanese Patent Laid-Open No. 2-276736.
No., No. 64-24024, No. 64-2664
As shown in each publication such as No. 6, means for providing a tongue for pushing up a bottom plate on which sheets are stacked is used.

[0003]

The center of rotation of the tongue is, as shown in FIG. 1, the contact point P ₁ with the tongue 3 at the lowest position of the bottom plate 2 of the paper tray ₁ and the bottom plate 2. It is often provided near the line connecting the rotation centers O ₁ , but in that case, the relative movement distance L between the bottom plate 2 and the tip of the tongue 3 in the movable range of the bottom plate 2 becomes unnecessarily long. Therefore, there is a concern that the durability of the two parts may deteriorate due to wear of both parts. This can be avoided by providing a driven roller on the tip portion of the tongue 3, but the cost becomes high.

Further, in a device for feeding paper by utilizing the rising force of the bottom plate 1 as it is for pressure contact with the calling roll and the feed roll 4, the tongue 3 is placed at the above position.
If the center of rotation is provided, the fluctuation of the pressure contact force due to the difference in the sheet stacking amount becomes large, and there is a problem that the sheet feeding capability becomes unstable.

The present invention has been made in view of the above, and the contact points between the tongue tip at the uppermost position and the lowermost position of the rotating bottom plate are hardly changed, and the bottom plate and the tongue tip are changed. It is possible to improve the durability of this part because there is no useless contact fluctuation of
It is another object of the present invention to provide a paper feeding device in which the force of pushing up the bottom plate can reduce fluctuations due to changes in the stacking amount of paper.

[0006]

In order to achieve the above-mentioned object, a paper feeding apparatus according to the present invention engages a movable sheet stacking member with the sheet stacking member by pivotal movement. In a sheet feeding device having a tongue configured to move a sheet stacking member toward a sheet feeding unit having a feed roll or the like, a line segment connecting both engagement points with the tongue at both boundary positions of the movable range of the sheet stacking member. It is arranged such that the center of rotation of the tongue is located on the substantially vertical bisector.

[0007]

[Operation] The engagement position with the tongue on the paper stacking member is
The position of the sheet stacking member is the same at both ends of the movable range, the deviation of the engagement point with the sheet stacking member during the rotation of the tongue is slight, and the relative movement of the tongue to the sheet stacking member is reduced.

[0008]

EXAMPLE An example of the present invention will be described with reference to FIG. It should be noted that members having the same configurations as those of the conventional one shown in FIG. The bottom plate 2, which is a sheet stacking member of the sheet tray 1, is configured to rotate from a substantially horizontal standby position shown in FIG. 2 to an uppermost position in a state shown in FIG. 3 where the last sheet remains. This rotation (lift-up) is performed by being pushed up by the rotation of the tongue 6 which is arranged below the bottom plate 2 so as to face it.

Now, the bottom plate 2 in the standby state (FIG. 2)
The pressing point by the tongue 6 is C ₁ . The position of C ₁ when the bottom plate 2 moves up to the uppermost position (FIG. 3) is C ₂ . At this time, C
₁ and C ₂ are located on the same radius from the pivot fulcrum O ₁ of the bottom plate 2. C ₁ and C ₂ are boundary positions of the movable range of the sheet stacking member. The rotation fulcrum O ₂ of the tongue 6 is arranged on the perpendicular bisector of the solid line connecting the two points C ₁ and C _2, and the shape of the tongue 6 is C at the standby position.
_The bottom plate 2 has a substantially V shape so as not to interfere with the front end of the bottom plate 2 when the front end is in contact with 1.

According to this structure, the tip of the tongue 6 comes into contact with C ₁ of the bottom plate 6 at the standby position, and also comes into contact with C ₁ (= C ₂ ) even when the bottom plate 6 is at the uppermost position. If the tip of the tongue 6 is in contact with almost the same position on the lower surface of the rotating bottom plate 6, the bottom plate 2 is pushed up by a slight deviation in the middle of the rotation range (FIG. 4). Further, as described above, since the bottom plate 2 is lifted up by the tongue 6 that contacts almost the same position regardless of the stacking amount of the sheet, the pushing force of the bottom plate 2 is changed due to the change in the stacking amount of the sheet. Get smaller.

FIG. 5 shows a friction-separation type sheet feeding device provided with a nudger roll 7, and in addition to the nudger roll 7, the feed roll 8 and the retard roll 9, on the leading end side of the sheet feed tray 1. A no-paper sensor (not shown) that detects whether or not there is paper in the paper tray 1, a paper position sensor 10 that detects whether or not the uppermost paper is in a position where paper can be fed, and the tongue described above. 6 is provided.

Prior to the start of paper feeding, the presence or absence of paper is judged by a signal from a no-paper sensor, and if there is paper, the tongue 6 is rotationally driven by a drive device (not shown) so that the tip of the tongue 6 is at the standby position. The bottom surface of the bottom plate 2 comes into contact with point C ₁ . Then, the bottom plate 2 and the sheets stacked on the bottom plate 2 are directly detected by the sheet position sensor 10
Is lifted up by the tongue 6 until the uppermost sheet is detected.

Therefore, the uppermost position of the bottom plate 2 is the position after lift-up when only one sheet is in the tray, and the tip of the tongue 6 at this position is the standby position of the bottom plate 2. It is contacted at the same position as the position (C ₁ ) that was in contact with this at one time. This allows
The range in which the tip of the tongue 6 moves along the lower surface of the bottom plate 2 is extremely short.

FIG. 6 shows a sheet feeding device of the corner naber system and FIG. 7 shows a sheet feeding device of the friction separating system which does not include a nudger roll. In the sheet feeding device of these systems, the tongue 6 is the same as that shown in FIG. The same operation as in the illustrated paper feeding device is performed. In FIG. 6, 11 is a corner snubber,
Reference numeral 12 is a feed roll, and in FIG. 7, 12 is a feed roll and 13 is a retard roll.

[0015]

According to the present invention, the contact points between the uppermost position and the lowermost position of the bottom plate, which is the rotating sheet stacking member, and the tip of the tongue hardly change, and the bottom plate and the tongue are not changed. There is no useless contact fluctuation,
The durability of this portion can be improved. In addition, the force that pushes up the bottom plate can reduce fluctuations due to changes in the paper load.

[Brief description of drawings]

FIG. 1 is a schematic configuration explanatory view showing a configuration of a conventional sheet feeding device.

FIG. 2 is an explanatory diagram showing the relationship between the tongue and the bottom plate of the paper tray in the paper feeding device according to the present invention.

FIG. 3 is an explanatory diagram showing the structure and operation of the tongue of the paper feeding device according to the present invention.

FIG. 4 is an explanatory view showing a state where the bottom plate is lifted up to the uppermost position.

FIG. 5 is an explanatory diagram showing an example in which a paper feeding method is different in the paper feeding device according to the present invention.

FIG. 6 is an explanatory diagram showing another example of the sheet feeding device according to the present invention, which has a different sheet feeding method.

FIG. 7 is an explanatory diagram showing another example of the sheet feeding device according to the present invention, which has a different sheet feeding method.

[Explanation of symbols]

1 ... Paper tray, 2 ... Bottom plate, 3, 6 ... Tongue, 4, 8, 12 ... Feed roll, 7 ... Najar roll, 9 ... Retard roll.

Claims (1)

[Claims] 1. A movable sheet stacking member, and a tongue which engages with the sheet stacking member by pivotal movement to move the sheet stacking member toward a sheet feeding unit having a feed roll or the like. In the paper feeding device having the above-mentioned, the rotation center of the tongue is located on a substantially perpendicular bisector of a line segment connecting both engaging points with the tongue at both boundary positions of the movable range of the sheet stacking member. Paper feeding device.